Over the past decades, sensor microsystems developed from simple transducers to a complete microsystem can include signal conditioning, analog-to-digital conversion, intelligence, and wireless link. Integrating sensors with electronic circuitry can offer several advantages, e.g., reduced size, weight, and cost, improved signal transduction, lower power consumption, and improved immunity to external noise sources.
Gas sensors find numerous industrial, medical, scientific, and military applications. One important application can include monitoring of toxic gases in oil and petrochemical industries. Another application can be building wireless gas sensor networks for environmental monitoring over large areas. Although the topic of gas sensing is relatively old, recent reviews show that the selectivity, dynamic range, and integration level of available gas sensors continue to fall short of the requirements of different applications.